A study of existent self-resettable door hinges or so-called door closers leads to the conclusion that as regards one type of hydraulical automatic door closer, it comprises a hydraulic system and a transmission lever to be installed to the top of the door and to the top of the door frame respectively, such a door closer will indeed achieve self-resetting effects for the door so provided, but its cost is rather high and the fitting is not easily done, as is often the case, besides, it calls for a rather large space and will have to be furnished with a hinge set before other fixture components can be fitted, so to speak, for such kind of hinged door closer it is a must to have three individual units prepared in order for fitting at three individual positions altogether before the automatical self-resetting performance of the door so provided can be expected, such a device is therefore regarded as a troublesome one, as regards another model of automatic hinge that is provided with screws and helical grooves and counterparts of these are also provided on the door involved of which transmission is derived from the gravity of the door as it is being pushed to open to give resetting strains to the door as exerted with respect to the helical grooves, the transmission principle for this door hinge set is simple enough, with little space requirements, still, it is not convenient for fitting, and by far not compatible for use with ordinary or regular doors, as prerequisite for application of such a door hinge is that the door itself be specifically made to accommodate fitting therewith to serve the purpose it is designed to serve; as regards still another kind of automatic self-resetting door hinge, for which transmission is derived from two-way screws and the strains of springs as parts thereof and other specifically devised components under the principle of applied mechanics, it is regrettable to find out that the resetting speed is not so regular or uniform and the strength of the springs can hardly be adjusted to a condition that is just right, what with a higher production costs, it is therefore not so recommendable for economical and performance reasons alike.